Vulnerability · Published Oct 15, 2026 · Assigned by VulnCheck
CVE-2026-111137libsmi through 0.5.0 Out-of-Bounds Write via smiValueAsString OCTET STRING DEFVAL
Medium 6.1
In plain English
A medium-severity out-of-bounds write in libsmi from amartin755. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 2% of all known vulnerabilities).
Official description
libsmi through 0.5.0 contains an out-of-bounds write vulnerability in smiValueAsString() in lib/smi.c that allows attackers to overflow a fixed 1024-byte static buffer through hex rendering of OCTET STRING values. Attackers can supply a crafted MIB with an OCTET STRING DEFVAL of 512 or more octets and a leading 0x00 byte to corrupt adjacent library globals and crash smidump or other consumers.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | libsmi | no fix listed | DEBIAN-CVE-2026-111137 |
| Debian:13 | libsmi | no fix listed | DEBIAN-CVE-2026-111137 |
| Debian:14 | libsmi | no fix listed | DEBIAN-CVE-2026-111137 |
| Ubuntu:22.04:LTS | libsmi | no fix listed | UBUNTU-CVE-2026-111137 |
| Ubuntu:24.04:LTS | libsmi | no fix listed | UBUNTU-CVE-2026-111137 |
| Ubuntu:26.04:LTS | libsmi | no fix listed | UBUNTU-CVE-2026-111137 |
| Ubuntu:26.10 | libsmi | no fix listed | UBUNTU-CVE-2026-111137 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| amartin755 | libsmi | 0 – through 0.5.0 |
Weakness: CWE-787 · Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:H
References
- https://hackmd.io/@haind-pwn/libsmi-smivalueasstring-octetstring-defval-oob-write technical-description, exploit
- https://github.com/amartin755/libsmi/blob/c58307210fe995ec419db976eb234aebc71a9216/lib/smi.c#L479-L566 technical-description
- https://github.com/amartin755/libsmi product
- VulnCheck Advisory: libsmi through 0.5.0 Out-of-Bounds Write via smiValueAsString OCTET STRING DEFVAL third-party-advisory